Peripheral blood stem cells (PBSC) were collected by two leukaphereses and cryopreserved in a 3-year-old girl with T-lymphoblastic leukemia; this was after remission was induced by an investigative regimen when she failed to respond to a first-line induction therapy. The patient received marrow-ablative chemotherapy 4.5 months after the diagnosis; this was followed by the infusion of thawed PBSC (203 x 10(4) CFU-GM/kg). The peripheral granulocyte count reached 0.5 x 10(9)/L by day +7 and the platelet count reached 20 x 10(9)/L by day + 9. Thereafter, the leukocyte count increased to 38 x 10(9)/L by day +14, with a gradual decline to normal levels. She has remained in unmaintained, complete remission 47 months after the autograft, with full school activity. This case illustrates the PBSC autograft is useful as an alternative to bone-marrow transplantation in a selected patient population, and extends the application of cure-oriented therapy to refractory childhood leukemia.